Fluid handling devices



April 1951 R. s. WADDlN GTON ETAL 2,980,033

FLUID HANDLING DEVICES Filed Feb. 26, 1957 2 Sheets-Sheet 1 50 5 5 5/ A25 g I 27 44 45 2.5 25 It. 4 42 39 4/ u 7 1-8- 20 I 40 [91 i T 49 /6 b47 Li. R 45 1 ROGOR STRANGE WAIIDINGTON AND BRUCg DUVAL A ttorneys April18, 1951 R. s. WADDINGTON ETAL 2,980,033

FLUID HANDLING DEVICES 2 Sheets-Sheet 2 Filed Feb. 26, 1957 8 N w m. 6 mm MD ML Wm v. E 0 6 ROGOR STRAN AND BRUCE D Unite FLUID HANDLING DEVICESRogor Strange Waddington, 6 Magdalene House, Manor Fields, Epsom,England, and Bruce Duval, 39 Cheam Road, Ewell, England The presentinvention relates to fluid handling means and has as an object theprovision of a device which enables fluids to be mixed together in asimple and automatic manner.

It has long been known that a primary-liquid flowing through a venturihaving an inlet passage connected with an intermediate point thereof,will draw a stream of secondary-liquid through that inlet passage. Suchknown forms of apparatus as incorporate such an arangement of venturiand conduit, for example flow meters and laboratory filter pumps, arenot however well adapted for general use as mixing apparatus, primarilybecause (a) the proportion of secondary-liquid pumped and mixed with theprimary liquid has, with the forms of venturi employed, been verysensitive to the rate of flow of the primary-liquid; (b) venturis aspreviously employed, although they have in some cases been capable ofproducing a very large pumping effect, have offereda considerableresistance to the flow of the primary-liquid.

It is an object of the present invention to provide an apparatus inwhich these defects are avoided and which thus constitutes asatisfactory mixing device for use even in establishments Where it isvirtually impossible to supply primary liquid at a constant rate of flowe.g. where a large number of water supply points are fed from a commonelevated cistern.

In accordance with the present invention there is provided apparatus formixing liquids which apparatus comprises a hollow body part the surfaceof which is shaped to define a venturi passageway for the passage ofprimary liquid through said body part, said passageway having anelongated throat section leading from a convergent inlet section to adivergent outlet section, having an inatt the primary-liquid stream asit passes through the venturi eluded angle of divergence of from 2 /2 to7 /2 (and therefore having its wall surfaces inclined to its axis atfrom 1%- to 3% which is terminated by a mixture outlet from said hollowbody part and to exhibit, when viewed from the direction of approach tosaid throat section, an annular surface portion surrounding said throatsection having an overall cross-sectional area greater, preferablysubstantially greater,'than the cross-sectional area of the mixtureoutlet and which annular surface portion consists at least in part ofthat portion of the surface of the body part whichdefines the convergentinlet section, said body part being formed with a secondary liquid inletpassage communicating with said throat s'ectionpreferably at a distancefrom the junction of said throatse'ction with said inlet section of A3of '%'of'the length of said throat section. As will be appreciated, partofthe surface of the body part, bounds the body part externally and partof said surface bounds the body part internally.

To. use thesaid apparatus for mixing a small proportion of asecondary-liquid with a primary-liquid, a supply of the secondary-liquidis connected with the sec-1 passageway.

Among the possible forms of the surface of the body part there may bementioned the following:

(a) The body part is formed with a flat end-surface, from the centre ofwhich the inlet section converges to meet the throat section; in thiscase the flat end-surface provides a part of the annular surfaceportion;

(b) The body part is formed with a sharp edge at its end, from whichedge the inlet section converges to meet the throat section;

(c) The body part is formed with an end-surface formation adapted toseat on the end of a primary-liquid supply conduit, the annular surfaceportion being surrounded by said end-surface formation and the outerpart of the surface of the body part being formed with a thread adaptedto be engaged by a union nut associated with the conduit or being formedwith a shoulder for locating a union nut adapted to engage a threadformed on the conduit;

(d) The body part is formed with an' internal surface portion whichjoins the periphery of the annular surface portion, said internalsurface portion being adapted to be fitted over the end of a primaryliquid supply conduit in screw-threaded or frictional engagementtherewith.

In order to illustrate the invention there is given the followingdescription, wherein reference is made to the accompanying drawings, ofa preferred embodiment of the mixing device. The said embodimentincorporates a shut-off valve for the secondary liquid as described inour copending application Serial No. 642,503. In the drawings:

Fig. 1 shows in vertical cross-section the embodiment which.incorporates a block valve assembly;

Fig. 2 is an elevation of the embodiment taken from the right as seen inFig. 1, the block valve assembly and parts 17, 27 and 28 being removed;Y i .Fig; 3"is the cross-sectiontaken along the line III -III of Fig. 2;y 1

' Fig. 4 isa vertical cross-section through a part of the device;

Fig. 5 an underneath plan ofthe embodiment as shown in Fig; 1 parts 53and 54 being removed;

Fig. 6 is a plan of the embodiment, while Fig. 7 illustrates a manner iswhich the embodiment may be put into use.

Referring to Fig. 1, the device shown therein comprises a body-part 1formed with a venturi passageway having an inlet section 2, an elongatedthroat section 3 and an outlet section 4 connecting a primary-liquidinlet 5 with a'mixture :outlet 6. The diameter of the primary-liquidinlet 5 is A inch and the diameter of the mixture outlet 6 is inch. Theinlet section 2 of theventuri passageway has a length of inch and'anangle of convergence (half conical angle) of 12 /2 The elongated throatsection 3 has a diameter of inch and length of 1 inch,

ondary-liquid passage and the annularsurface portion is I arranged, byappropriately'connecting the body part with.

while the outlet section 4 has an angle of divergence (half conicalangle) 'of 2 /2 and a length of 1 inches, giving a total length for thebody part and for the venturi pas sageway of 2 inches.

Water supply company regulations usually specify. that the height of thelower end of a tap connected with the supply mains .must be at least 3inches above the top of the waste outlet from thesink. or-otherfixedreceptacle" This effect over which it is installed and that anyanti-splash device or other extension connected with the tap must notexceed 3 inches in length. The result of these regulations is to avoidthe submergence of the tap or any extension con nected thereto below themaximum water level, thereby avoiding any possibility of contaminatedwater being drawn back into the supply mains when the supply of water isinterrupted. In consequence the overall length of the apparatus shown inthe drawings is such as to render it acceptable virtually universally.

A secondarydiquid inlet passage 7 of diameter "X inch formed in the wallof the body part and entering the elongated throat section 3 at adistance of A3 inch from the primary liquid inlet is provided forleading secondary liquid to the throat section 3. As shown most clearlyin Fig. 4 the outer end of the valve chamber is countersunk at 9 andcontains a piston assembly (omitted for the sake of clarity from Fig. 1)which piston assembly consists of a stem 10 terminating in a piston 11having a close fit within the valve chamber and, on the side of thepiston opposite from the stem, a component 12 adapted to fill theconduit 7 substantially completely. The component 12 is, in the caseshown, formed of soft rubber in order to provide a liquid-tight seal forthe conduit 7. It may however be, and preferably is, formed of hardsteel or other metal ground to fit the passage closely. The stem part ofthe valve assembly passes through a rubber washer 13 which rests in thecountersunk end of the valve chamber and whose central aperture has aclose fit with the stem 10. A metal washer 14 placed over the rubberwasher 13 serves to accept the reaction of the lower end of a helicalspring 15 the other end of which bears against a small knob 16 of nylonor other lowfriction plastic material at the head of the stem. The head16 bears against the inner cam surface of the skirt of a cam ring 17which is rotatably mounted upon the body part, the said skirt portionhaving a cylindrical inner surface which is formed eccentrically withthe axis of rotation of the cam ring, thereby causing the piston '11 tobe moved within the valve chamber when the cam ring is rotated. Indexmarkings on the cam ring (not shown) enable the ring to be set forspecific concentrations of secondary-liquid in the mixture. For limitingthe rotation of the cam ring, and thus limiting outward movement of thepiston, there is provided a rotatable set-ring 18 which carries a peg 19adapted to engage a peg 20 which projects from the inner surface of thecam ring. A set-screw 21, Which is formed with a cruciform or otherspecially-shaped recess'in its head so that it can only be moved bymeans of a complementary key is provided for locking the set ring 18 andconsequently setting the stop 19 in a position corresponding with thedesired maximum outward limit of travel of the piston as sembly. Furtherlimiting means for the rotation of the cam ring 17 are provided by aprojection 22 formed on the body part, which projection is adapted toengage the ends 23 and 24 of a circular keyway formed in the undersurface of the cam ring contiguous with the central aper-,

ture thereof. For locating the cam ring in its correct position upon thebody part, thebody part is formed with shoulders 25 and 26 adapted toco-operate with complementary formations surrounding the centralaperture of the cam ring. A metal washer 27 retainedin posi. tion by asplit ring 28 which rests in a complementary groove 29 formed in theouter surface of the body part serves to hold the cam ring againstwithdrawal. Above the groove 29, the exterior of the body part isprovided with a pair of grooves 35% and 31 which serve to assist informing a strong connection when the device is connected by means of ashort length of rubber tubing to the tap with which it is to be used.Theexternal diameter of the body part at this position is inch.

For supplying the secondary-liquid to the valve cham be'r 8, there isprovided an internal passageway 32 formed by a long bore from the end ofthe body part to a small junction chamber 33 bored into the body 'partfrom a cylindrically walled flat-bottomed recess 34 formed in the outersurface thereof. The part of the long bore between the upper end of thebody part and the valve chamber 8 is then fiiled throughout its lengthby means of a rod 35 cemented therein. In this way the passageway 32 isconveniently formed even though neither end is readily accessible forboring.

Secured to the side of the body part 1 with its end portion locatedwithin the recess 34 is a block valve assembly secured in position byscrew 36 which enters a tapped hole 37 in the body part 1. A fibregasket 38 placed in the bottom of the recess 34 ensures a fiuidtightconnection between the block valve assembly and the body part. The blockvalve assembly consists of a body part 3? formed with a large bore 40which lies parallel with the axis of the venturi passageway in the bodypart 1 and extends from the under-surface of the part 39 to meet a shortbore 41 formed coaxially therewith from the top of the part 39. Securedwithin the short bore 41 is a nipple =42. At its upper end the nipple 42is provided with a seating surface 43 below which is formed a threadedsection 4-4, this arrangement enabling a secondary-liquid supply tube tobe secured by means of a suitable union nut. A horizontal bore 45 formedthrough the part 39 and passing through the bore 40 gives access duringassembly to the screw 36. In the finally assembled device the outer endof the borev 45 is sealed by a plug 46 as shown. Located within the bore4% is a tightly fitting plug 47 provided with a raised rim 48 at itslower end. A piston valve comprising a stem portion 49 of roundedtriangular cross-section, a head portion 59 and a washer 51, has itsstern passed in loose sliding relationship through a cylindrical bore 52formed on the axis of the plug 47. The stem portion 49 of the pistonassembly rests upon a rubber diaphragm 53 retained in position by a plug54 provided with an upper circumferential ridge 55 which seals the lowerend of the bore 40. The circumferential ridge 55 is perforated at 56 toprovide communication between, on the one hand, the space between theunderside of the diaphragm 53 and the upper surface of the plug 54, andon the other hand, a passageway 57 bored through the body part 39 atsuch an angle as to communicate with a junction chamber 5'8 formed inthe recess in the body part 1. This junction chamber 58 cumminicates viaa passageway 59 with the upper end of the body part 1. A furtherpassageway 60 (Fig. 5) is formed through the part 39 to connect thejunction chamber 33 with an aperture formed through the rim 4% on theplug 47 and thence to the upper side of the diaphragm 53.

With the apparatus shown in Figs. 1 to 6 connected with a tap or othersupply of primary liquid by a short length of rubber tube having its endpushed over the grooves 39 and 31 and the nipple 4-2 connected with asupply of secondary-liquid, flow of the secondary liquid to the valvechamber 8 is prevented until primary-liquid is passed through theventuri passageway and the pressure of the primary-liquid at the upperend of the apparatus is applied to the underside of the diaphragm 53 viapassageway 59, junction chamber 58, passageway 57 and aperture 56. Theeffect of this pressure is to deform the diaphragm and raise the piston56 and washer 51 so that secondary liquid can fiow through the clearancespace between the stem 49and the wall of the bore 52 to reach the valvechamber 8 via bore 69, junction chamber 33 andbore 32. Assuming thatthecam ring 17 and consequently the piston assembly are in the relativepositions shown in Pig. 2, the throttling effect of the venturipassageway draws secondary liquid into the stream of primary liquid sothat a mixture of primary and secondary liquids emerges from the mixtureoutlet 6, the. actual strength of the mixture depending upon the preciseposition of the cam ring 17 and the corresponding position of the piston11 relative to the orifice 61 with which the bore 32 communicates withthe valve chamber -8. Outward movement of the piston .11 from theposition shown in Fig. 2 causes the orifice to become relatively moreuncovered and thus to increase the concentration of secondary-liquid inthe mixture emerging from mixture outlet 6; while inward movementresults in a more complete covering of the orifice 61 and thus reducesthe said concentration. If while the primary-liquid is flowing the camring 17 is rotated to push the piston assembly inwardly by reaction ofthe head 16 thereof, to such an extent that part 12 fills orsubstantially fills the conduit 7, the supply of secondary-liquid isinterrupted and moreover the complete filling or substantially completefilling of passage 7 by part 12 ensures that no pocket ofsecondary-liquid is left in contact with the stream of primary-liquid.Consequently, primary-liquid is almost immediately obtained from themixture outlet 6 in uncontaminated condition.

When the flow of primary-liquid is interrupted its pressure ceases to beapplied to the underside of the diaphragm 53. The washer 51 consequentlyfalls into contact with the upper surface of the plug 47 and thus sealsthe secondary liquid supply from the valve chamber. If for any reasonthe outlet 6 is blocked and the primary liquid supply is operated insuch a manner as to provide a vacuum effect, secondary-liquid cannot bedrawn into the primary liquid supply and cause undesirablecontamination.

It will be noted that the block valve assembly, being mounted on theside of the apparatus does not increase the overall length thereof.

When the device shown in Figs. 1 to.6 is connected to a /2 inch watertap supplied with a 20 foot head of water-pressure through /2 inchpipework, a rate of flow is obtained from'the mixture outlet which isonly 30% less than that obtainable from the water tap before connectionof the device. This small reduction in the rate of flow is obtainedsimultaneously with a high pumping efficiency; for example when suppliedwith water under a head of only 7 feet the device is capable of liftingwater supplied as secondary-liquid through a height of 5 feet.

The ability of the device to give a mixture whose concentration isinsensitive to the variations of the rate of flow of the primary-liquidas are likely to be encountered during normal use is illustrated by thefollowing table:

Concentration of mixture in fluid ounces per gallon Arbitrary setting ofHead of Water Pressure at $4" tap cam ring The use of the device isillustrated diagrammatically in Fig. 7 which shows a tap A supplied by apipe B lead ing for example from an overhead cistern or water supplymains and having the device attached thereto by means' of a rubberconnector C. A rubber or other tubeD passes from the nipple and joins acoppertube E which dips to the bottom of detergent liquid in a can Fplaced under the sink G over which the tap A is installed. The lower endof the. tube E'is fitted with a housing H, adapted to pass through themouth of the can and containing a filter for the detergent liquid and anon-return valve which ensures that the tube D and the secondary-liquidpassageways in the device remain filled with detergent between mixingoperations.

It will be appreciated that the specific embodiments of the mixingdevice provided by the present invention which are described herein aregiven merely by way of illustration and that various departures may bemade therefrom without departing from the scope of the inventionclaimed. Y

.We claim:

, 1. Apparatus for mixing liquids which apparatus comprises a hollowbody part the surfaces of which are shaped to define a venturipassageway for the passage of primary liquid through said body part,said venturi passageway having an elongated throat section leading froma convergent inlet section to a divergent outlet section which has anincluded angle of divergence of from 2% to 7 /2 and which is terminatedby a mixture outlet from said hollow body part and to exhibit, whenviewed from the direction of approach to said throat section, an annularsurface portion which surrounds saidthroat section and has an overallcross-sectional area greater than the cross-sectional area of themixture outlet and which annular surface portion consists at least inpart of that portion of the surface of the body part which defines theconvergent inlet section, said body part being formed with a secondaryliquid inletpassage communicating with said throat section at anintermediate position thereon.

2. Apparatus according to claim 1 in which the body part is formed witha flat end surface from the centre of which the inlet section convergesto meet the throat section has an axial length which is from two to sixabout 5.

5. Apparatus according to claim 1, in which the included angle ofconvergence of the inlet section is from i 20 to 30.

6. Apparatus according to claim 1, in which the in cluded angle ofconvergence of the inlet section is about 25.

7. Apparatus according to claim 1, in which the inlet section has alength which is at least as great as the trans-- verse dimension of thethroat section.

8. Apparatus according to claim 1, in which the .outlet times thetransverse dimension of the throat section.-

9. Apparatus according to claim 1, in which the throat section has adiameter of about 7 and thesecondary liquid inlet passage has a diameterof about 6 10. Apparatus according to claim 1 in which the secondaryliquid inlet passage communicates with the throat section at a positionwhich lies at a distance of from A; to of the length of the throatsection from the junction of the inlet section and the throat section.

' 11. Apparatus for mixing a secondary liquid with water from a tapwhich apparatus comprises a body part provided with a connector operableto engage the tap and formed with a venturi passageway for the passageof water from within the connector through the body part, said venturipassageway having a convergent inlet section leading from within theconnector to an elongated throat section whose'length and transversedimensions are in av ratio of at least 3:1 and said throat sectioncommunicating with a divergent outlet section in which the boundarysurface of the venturi passageway diverges fromthe axis 8 municatingwith said throat section at an intermediate 1,897,492 Ledoux Feb. 14,1933 position thereon. 1,937,893- Hutton Dec. 5, 1933 2,168,363 Pos Aug.8, 1939 References Cited in the file of this patent 2:300642 Booth NOV.3, 1942 UNITED STATES PATENTS 5 2,353,759 Ray July 18, 1944 911,000pitzgibbon J 2 1909 2,795,460 Bletcher et a1 June 11, 1957 ,035,348Ledoux Jan. 27, 1914 2,797,132 Alpert ne 25, 1957 1,311,861 Earl July29, 191 FOREIGN PATENTS 1,321,856 Slater Nov. 18, 1919 10 7 1,748,488McCabe Feb. 25, 1930 693,804 Germany Nov, 18, 1940 1,753,662 Merker Apr.8, 1930 UNITED STATES rATENT Or'FICE CERTIFICATE OF CORRECTION PatentN00 2980 033 April 18 1961 Rogor Strange Waddington et ale It is herebycertified that error appears in the above numbered patent requiringcorrection and that the said Letters Patent. should read as "correctedbelow In the grant lines 1 and 2( address of first inventor for "ManorFields Epsom England read Manor Fields Putney England =-=3 in =t.heheading to the printed specification lines 3 and 4 address of firstinventor for "6 Magdalene House Manor Fields Epsom England,,' read er 6Magdalene House Manor Fields Putney England e Signed and sealed this24th day of October 1961o (SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer I Commissioner ofPatents USCOMM-DC-

